• 대한기계학회논문집
• /
• 제4권3호
• /
• pp.113-118
• /
• 1980

Stresses were calculated for finite-width orthotropic laminates with a circular hole and remote uniaxial loading using a two-dimensional finite-element analysis with both uniform stress and uniform displacement boundary conditions. Five different laminates were analyzed: quasi-isotropic [0.deg./.+-.45.deg./90.deg.].$\_$s/, 0.deg., 90.deg., [0.deg./90.deg.]$\_$s/, and [.+-.45.deg.]$\_$s/, Computed results are presented for selected combinations of hole diameter-sheet-width ratio d/w and length-to width ratio L/w. For small L/w values, the stress-concentration factors K$\_$tn/ were significantly different for the uniform stress and uniform displacement boundary conditions. Typically, for the uniform stress conditions, the K$\_$tn/ values were much larger than for the infinite-strip reference conditions; however, for the uniform displacement conditon, they were only slighty smaller than for this reference. The results for long strips are also presented as width-correction factor. For d/w.leg.33, these width-correction factors are nearly equal for all five laminates.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.433-436
• /
• 2002

Retardation liquid crystal films with a profiled titled optic axis (splay films) of both nematic and discotic types are used as compensation films for twisted nematic displays (TN-LCD). A new method is developed to characterize retardation vs. inclination (retardation profile) of splay films by three parameters: "full retardation" $d^{\ast}{\triangle}n$, "inplane retardation" $R_0$ and "retardation difference" $R_d$ . Splay films with the same retardation profile but with different tilt profile (retardation invariants) are discovered. Splay films with different structure parameters but belong to the same retardation invariant have the same compensation opportunities for TN-LCD.

• 생태와환경
• /
• 제42권4호
• /
• pp.465-475
• /
• 2009

The purpose of the study was to evaluate spatial and temporal effects of wastewater treatment plants (WWTPs) on the water quality of downstreams (Tan Stream, TS; Daemyeong Stream, DS; Gwangju Stream, GS, and Kap Stream, KS) located in four major watersheds along with impact analysis of nutrient enrichments on the WWTPs during 2004~2008. In the four streams, seasonal means of BOD, COD, TN, and TP were significantly (p<0.01) greater in the downstreams ($D_s$) than the upstreams ($U_s$). The removal effect of nutrients (nitrogen, and phosphorus) from the WWTPs was much less than the BOD, indicating a greater nutrient impact on the downstreams. Seasonal dilution of organic matter, based on BOD, during the summer monsoon of July~September was most pronounced in the downstreams of all four watersheds. However, mean TN in the downstreams during the monsoon varied little in all four streams. Regression analysis of TN in the downstreams against TN from the WWTPs showed that in the TS, and DS regression slopes in the upstreams were similar to the slopes of downstream but there was a significant difference in the GS (p<0.001) and KS (p<0.01). Tan-Stream WWTP showed low removal efficiency of BOD and COD concentrations, compared to the nutrients, whereas, two WWTPs of Gwangju and Kap Stream had low removal effects in TN and TP. Regression analysis of TN and BOD in the downstreams showed that they was closely related (p<0.01) with stream water volume only in the GS. Our data analysis suggests that greater treatment efficiencies of phosphorus and nitrogen from the WWTPs may improve the downstream water quality.

• Journal of Animal Science and Technology
• /
• 제49권2호
• /
• pp.279-286
• /
• 2007

반응물을 연속적으로 내부 순환시키는 생물막 연속회분식모래여과 공정을 고안하고 외부 탄소원이 전혀 사용되지 않는 조건하에서의 돈사폐수 처리특성을 평가하였다. 수직형과 경사형 모래여과조에서의 NOx-N 부하량에 따른 탈질율은 각각 19%와 3.8%로 수직형에서 5배 정도 높은 효율을 보임에 따라 수직형태의 모래여과조를 생물막 연속회분식 공정과 연계하여 운전하였다. 처리공정을 HRT 15일, 내부순환율 105L/hr.m3, 평균 암모니아성 질소 부하량 54g/m3.d 조건에서 운전하였을 때 STOC, NH4- N, TN의 처리효율은 각각 75%, 97%, 85%이었다. 생물막 연속회분식 반응조와 모래여과조간의 내부순환으로 TN의 제거효율이 약 14%증진되는 것으로 나타났으며 얻어진 질소제거효율 증진은 주로 모래여과조에서의 탈질에 의한 것으로 밝혀졌다. 또한 용해성 인의 경우 내부순환이 수행되지 않았을 시에는 유출수내 농도가 오히려 증가하였으나 내부순환시에는 약 57% 정도가 제거되는 것으로 나타남에 따라 반응물의 내부순환이 용해성 인의 제거효율 증진에도 기여함을 알 수 있었다. 시스템에서의 질소제거 양상을 분석해본 결과 최종 유출수내의 NH4-N은 부하량 60g/m3.d 수준에서 약 20mg/L 이하로 비교적 일정하였고 부하량이 100g/m3.d. 이상의 수준으로 상승함에도 80% 이상의 질소 제거효율을 보였다. 그러나 부하량 100g/m3.d 수준 이상에서부터 처리효율이 감소하는 것으로 나타나 외부탄소원이 전혀 사용되지 않는 운전조건에서의 질소의 적정 부하량은 약 100g/m3.d 정도인 것으로 판단되었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.290-292
• /
• 2007

A twisted nematic type liquid crystal electro-optic modulator (TN-LC modulator) was developed. The modulator used single polarizer and the reflection on-off ratio was maximized by optimization of twist angle and retardation of liquid crystal cell. The TNLC modulator shows better sensitivity and response time than conventional liquid crystal modulator.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.1125-1131
• /
• 2004

We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with rubbing alignment method on the two kinds of polyimide (PI) surfaces using thin plastic substrates. The NLC pretilt angles generated on thin plastic substrates are higher than that on the glass substrate. We study that AFM (atomic force microscope) image of rubbed PI surface with polymer film has formed the micro-groove. Also, EO characteristics of the TN-LCD with a rubbed PI surface based on polymer are almost the same as that of the TN-LCD with a rubbed PI surface based on glass.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.914-917
• /
• 2002

We have obtained high performance and low voltage driving OCB panel by reducing the critical voltage and retardation matching between liquid crystal layer and compensation films. The critical voltage in the panel has been minimized by flattening color filter layer and optimizing a rubbing process. In addition, an appropriate retardation of the film and LC layer has scanned to achieve low driving voltage and high transmission. The proto-type 17" WXGA OCB panel has demonstrated with less than 5V drive and over 80 degree for all viewing direction except for rubbing direction with over 90% of TN light efficiency.

• 한국해양환경ㆍ에너지학회지
• /
• 제20권2호
• /
• pp.76-83
• /
• 2017

본 연구에서는 시화호 유역 하천수의 일반수질 및 중금속의 변화 및 유출특성을 파악하기 위하여 시화호로 유입되는 하천수 중 일반수질 및 중금속의 분포 특성, 토지이용형태에 따른 농도비교 및 하천을 통한 유출부하량 조사를 실시하였다. 시화호 유역 하천을 토지이용형태에 따라 산업지역, 도심 및 농업지역으로 구분하여 일반수질 농도 비교를 실시하였을 때, 하천수 중 DO, SS, POC, $NO_3$와 Chl-a는 농업지역이 산업 및 도심지역에 비해 높은 농도를 보였으며 COD, DIN, $PO_4$, TN, TP, DOC와 TOC는 산업지역이 상대적으로 높은 농도를 보였다. 하천수 내 수질 및 중금속 분석항목에 따라 약간의 차이가 존재하지만, 3월~5월 조사시기에 상대적으로 농도가 높고 7월~8월에는 강우에 의한 영향으로 농도가 감소하는 결과를 보였다. 하천유량과 농도를 이용하여 계산된 일반수질의 유출부하량은 SS 1,172 kg/d, TN 151 kg/d, TP 11.1 kg/d, TOC 389 kg/d이었고, 농업지역인 장전보가 전체 유출부하량에서 47.5%(TP)~75.1%(SS)를 차지하고 있었다. 하천수 내 Cu, Zn, Cd은 산업단지 하천을 통한 유출부하량이 전체의 92%를 초과하고 있는 것을 알 수 있었으며, Zn>Cu>Ni>Pb>Co>Cd의 순으로 나타났다.

• 대한화학회지
• /
• 제48권2호
• /
• pp.123-128
• /
• 2004

폴리아민과 이미다졸 유도체에 대해서 AM1, PM3, ZINDO/1법으로 형성엔탈피(${\Delta}H_f$), HOMO, LUMO에너지 및 쌍극자힘(${\mu}_D$) 값을 얻었다. 이들 리간드를 Ni(II)에 배위시킨 Ni(II)착물의 저해활성효과를 ZINDO/1(Zerner''s Intermediate Neglect of Differential Overlap No.1)법으로 조사하였다. Ni(II)착물의 중심금속의 알짜전하 값이 0.03 이상과 형성엔탈피가 음의 값으로 300 eV이상에서 실험적인 저해활성 값이 나타남을 보였다. 그 결과 Ni(II)착물은 불안정한 5배위 사각피라미드형인 [Ni(dpt)(tn)]$^{2+}$(dpt=3,3''-diaminodipropylamine)(tn=1,3-diaminopropane)와 일그러진 사면체인 [Ni(N-PropIm)$_2$(NCS))$_2$](N-PropIm=N-Propylimidazole)를 제외한 착물에서는 저해활성 값이 나타남을 알 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.1049-1052
• /
• 2004

In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode